MEXICO CITY, May 7, 2024 (BSS/AFP) - Prisoners awaiting trial or sentencing began voting Monday in Mexico's presidential election from inside jails -- a first for the Latin American nation.

Ballot boxes were installed on tables in the auditorium of a men's prison in Mexico City emblazoned with the words: "The vote is free and secret."

Prisoners' thumbs were marked with indelible ink to show their early participation in the June 2 election, which is expected to produce Mexico's first woman president.

"We just hope that they (the candidates) are true to their word, more than anything so that things can improve for us and our families," said one inmate, whose identity cannot be revealed for legal reasons.

The 24-year-old is one of more than 30,000 prisoners in preventive detention who are allowed to vote inside jails for the first time this year.

As well as voting for the next president, he also cast ballots for the Mexico City mayor, local and national lawmakers and a local district mayor.

"They brought us the campaign material, we saw the debates and all that, and we can base our vote on all of that," the inmate told reporters invited to watch the voting.

In the same men's prison in the north of Mexico City, 354 of the 1,862 inmates were allowed to vote after an electoral tribunal decided in 2019 that unsentenced prisoners have the right to cast ballots.

"For me the most important message is to tell them as an electoral authority that we recognize the rights they have," said Maria Luisa Flores, a National Electoral Institute official.

"They are people who are in preventive prison, that is to say, they do not have a sentence, therefore they still have their political electoral rights in force," she added.

"It is a historic morning, not only in Mexico City, but for the whole country," Flores said of the voting, which is planned to take place in 282 prisons.

Around 31,000 inmates nationwide -- roughly 13 percent of the total of more than 230,000 -- met the requirements to vote, the government said.

According to an average of polls compiled by the firm Oraculus, the ruling party candidate, former Mexico City mayor Claudia Sheinbaum, is the frontrunner with 57 percent of voter support.

In second place is Xochitl Galvez -- an outspoken businesswoman and senator representing the main opposition coalition -- with 35 percent.

Jorge Alvarez Maynez of the Citizen Movement party is a distant third with nine percent.